


quantum merlin arthur games (i’ve got a war in my mind)

by birdsofthesoul



Series: pseudoscience babble [1]
Category: Supernatural
Genre: Aftermath of Possession, Alternate Season/Series 14, Blatant Abuse of Physics, Consent Issues, Gen, Hurt Dean Winchester
Language: English
Status: Completed
Published: 2019-04-13
Updated: 2019-04-13
Packaged: 2020-01-12 22:49:59
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,667
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18456218
Author URL: https://archiveofourown.org/users/birdsofthesoul/pseuds/birdsofthesoul
Summary: Michael comes in waves, until he doesn’t. Sam goes on a QMA-complete hunt for Dean.Or: Dean’s life devolves into a k-local Hamiltonian problem as Sam tries to rip Michael out of his head.





	quantum merlin arthur games (i’ve got a war in my mind)

**Author's Note:**

> A huge thank you to eatdirt for her lovely artwork and unparalleled patience.

 

1.

Cas bids them good-bye three days after Dean’s migraine starts. Michael comes in waves, he says. Dean does not dispute this – Michael is a multidimensional waveform of celestial and murderous intent. He may be a high school dropout, but he’s done the math: that flimsy door in his head is maybe a billion meters thick on a good day.

Michael hurtles along at 300000000 m/s.

So you see then, Cas says sadly. All I can do is buy you some time.

How, asks Sam. His voice is a low rumble in his chest, a mini earthquake at Dean’s back. Dean trembles in his brother’s arms and tells himself that he’s an open-circuited line.

Cas is a theorist; he doesn’t understand impedance discontinuities or how to be one. Michael may be light, he offers, but he still travels in spacetime.

It’s a grandiose name for Dean’s nuthouse of a head, but Dean understands the urge to put a coordinate system to things. What do you want me to do, he slurs.

Nothing, Cas says. I’ll do my best to distort his path, he promises, and then he collapses into a steady stream of gravitational waves.

Goddamit, Sam says. He always goes for the classical solution.

It’s not much of a solution at all. There is a supernova of pain somewhere between the base of Dean’s skull and the back of his eyes, and somewhere in the recesses of his memories there are two black holes colliding into each other, God’s sons made monstrous through time. An eternity passes, leaving him boneless.

Dean, Dean, Sam shouts, and Dean finds enough air in his lungs to moan. He’s leaning against all of their pillows, and Sam’s a blurry shape in front of him, large hands splayed on Dean’s chest and knee as he pins Dean into existence. Sam, Dean says, and he thinks he’s crying.

Sam’s face crumples and he leans in, scoops Dean up and hushes him. It’s just Cas doing the time warp at Rocky’s, he says.

DEAN, Michael booms. DEAN—

— and Dean decoheres.

 

2.

Wake up, Sam says, and Dean shudders to life.

Michael, is Michael still in there? What do you remember? How are you feeling? _Dean, can you hear me?_ Sam is relentless. Sam has always been relentless.

I don’t know, Dean says silently, and Sam presses his lips together.

Say something, he says, and his hand is a vice on Dean’s shoulder. Dean tilts his face up, look into Sam’s eyes, and Sam looks back almost dispassionately, _surveys_ him for a moment, and then moves his hand to Dean’s temple. What’s going on in here, he asks quietly.

This is a question beyond Dean’s pay grade. Dean’s head is a probability distribution and time is just a phase factor. There’s not much of him present right now, he thinks – there’s a little of him in 1991, just enough to scrape off the sidewalk in 1995, and some parts of him are scattered throughout the aughts. In 2016, Sam looks at Dean like Father Lucca looked at his relic and Dean thinks he might be happy.

Dean doesn’t know what he is right now.

I messed up, Sam says, and his voice cracks.

Dean looks down at the sheets tangled in his fists. There is a dull ache in his bones, the feeling that someone somewhere hollowed him out, and when he swallows gingerly, wets his cracked lips before he tries to speak, he finds that someone has taken a cheese grater to his throat.

You kept screaming. Sam doesn’t avoid his eyes, but he’s not really looking at Dean. That’s fine with Dean; there’s not much to see anyway.

I had to stop before you did any permanent damage to yourself, Sam says, but what he means is I had to stop before I screwed you up anymore. He gets up, turns his back like he can’t bear to look at Dean anymore. There’s a pitcher of water on the dresser and Sam pours him a cup.

Dean doesn’t want water, but he takes it when Sam pushes the cool glass into his hands. Sam doesn’t come back to the bed. He keeps pacing, words spilling out urgently now. He wouldn’t leave, Sam says pleadingly. I tried to rip him out and it mostly took, but then he buried himself deeper, and now –

Now Michael’s embedded like shrapnel.

There’s only a little of him left, Sam promises. I’ll get all of him out, but you need to give me time.

This is a promise that is alarming in its familiarity.

Sam knows this too. I’m not going to put you through that hell again, Sam says.

He’s talking about Chinatown. He’s talking about the dirty motel room where Dean lay face-down on the soiled bedspread as his brother dug through his back with a knife.

He didn’t scream that time. Bit down on his fist until his knuckles were bloody, and told himself to man up for his twelve-year-old brother.

Sam sits down at his bedside. I left your back a mess that time, but you didn’t make a sound, he says. He laughs humorlessly. Can’t imagine the state I left your head in.

He lets out a shaky breath and fishes out a crumpled half pack of Marlboros.

Dean watches him fumble with the lighter. It takes a few tries for the flame to catch.

Tell me you’re still here, Sam says, taking a drag. At least let me know that you’re not blood and bone. He looks at Dean expectantly, like he’s waiting for an answer or at least a nod, but Dean doesn’t have that in him.

Sam looks like Dad from where he’s sitting, half shrouded in darkness, wreathed in smoke. There is a script, Dean thinks, and this is his cue.

It passes him by.

Sam’s eyes darken.

Dean drifts back to 2016.

 

 

3.

They lock up the bunker in the morning. Sam leaves the books, Dean’s box, the BMOL machine; he leaves everything except for the duffel bags they carried here six years ago. None of this is going to help me get you back, he says.

Dean is right here, but Dean as of 2019 is not enough for Sam. Sam is a purist – always has been and always will be.

This is delicate work, Sam is saying. I don’t have a choice, I _have_ to use my powers, anything else is a butcher knife.

Powers, Dean says, and Sam just looks at him sadly.

I got them back a while ago, his brother says gently. Did you forget again?

The streetlights flicker violently and Sam says loudly, I can’t go rooting through his head again, Cas, what if I fuck him up completely, and Dean think _Cas._

Where’s Cas?

Here, Sam says absently. He can’t get back inside his vessel, so he’s just around.

It suddenly occurs to Dean that maybe they’ve both lost their minds. Maybe the Winchesters have finally gone off the deep end and no one knows. Maybe this is the ending he saw seven years ago when the Great Wall of Sam came crashing down; maybe Sam’s going to put the car in drive and just go, over the bridge, the cliff, the Grand Canyon, over everything and straight into the Empty.

Maybe Sam is done, in the way Dean is.

The streetlights keep buzzing.

And then Sam says, what do you mean, k-local? What’s k?

He puts the car in park. They’re in the middle of a road and Sam doesn’t even bother to pull over.

The streets go dark.

Sam is still talking. What if I make a mistake, he asks. How do I undo it? Is that even possible? I can’t clone his current state of mind, Cas, I’m pretty sure there’s some theorem about this out there.

The radio in the Impala sparks to life and Cas says, what about quantum Merlin Arthur amplification?

Sam goes quiet.

The headlights of an approaching truck light up the inside of the car, and Dean sees that his brother is crying silently. Sam’s a messy crier, he thinks. Always has been.

He’s not anymore. Looks like Dean doesn’t know his brother as well as he thought.

This, though, is nothing new.

The truck honks. Dean thinks it’s a nice alternative to the earsplitting silence they’ve been sitting in.

How long, Sam asks at last.

Depends on your delta, Cas says. How much accuracy do you want?

 

4.

So here’s the thing about the k-local problem: it’s QMA complete, which means it’s anyone’s guess as to when Sam is going to find the equilibrium state.

What equilibrium state, Dean wants to ask. What problem? What’s k?

You’re the equilibrium state, Sam says, kneeling before him. He has Dean situated on the stained sheets of a skanky motel bed, and he’s finally stopped pacing and rambling about heuristics and folklore. Everything that’s happened to you so far – that’s the Hamiltonian, that’s our k-local problem.

Sam doesn’t know what k is. Could be forty, could be eighty.

It doesn’t matter to me, Sam says.

What he doesn’t say is that it matters to the runtime – that forty and eighty is the difference between getting your brother back in this lifetime and chasing him into the next.

Dean knows a little something about the quantum Metropolis too, courtesy of late night conversations with Cas, and the odds don’t look good on paper.

You wanna sample the subspace of my memory, he asks at last, and Sam just looks up at him hopefully.

It’s a pretty big subspace. Michael and Cas crammed two immortal lifetimes in there when he was otherwise occupied.

Just leave that to me, Sam says. Just tell me if I have your permission.

How would you know?

Know what?

If you find me?

Dean knows Sam very well, but the opposite has never been true. Dean’s right here and Sam still thinks that he needs to bring his brother home.

There’s a difference between kicking Michael out and finding the real Dean.

Dean doesn’t think the latter exists.

Your memories, Sam says carefully. Michael’s in the details. He’s gonna want to fool me, but I’m prepared this time.

What Sam means to say is that Michael is Merlin and Sam is Arthur. And Dean – Dean is just a quantum state.

There is something astronomically unjust about this situation where Sam is the only verifier of Dean’s memories.

This isn’t fair, Dean thinks.

Well, boo fucking hoo says John and his many ghosts. You two are entangled anyway.

Are you gonna restore my memories, asks Dean.

In a way, Sam says.

What goes unspoken is the qualifier – with delta accuracy.

Delta is pretty big from where Dean’s standing.

 

 

5.

Sam needs unitaries if he wants to run the quantum Metropolis on Dean, and he’s playing fast and loose with his operators. I’ll make do with memories, he says, like he wrote a thesis on why something so imperfectly preserved can serve as a quantum operator in something that really isn’t a quantum computer.

You know where to look, Dean says.

Let’s get a better room for this, Sam says, like the squalor of a no star motel is cramping his style. How does a three star hotel sound?

Three star hotels in Greater LA cost a little more than Sam expects. Sam let cards and financial fraud go by the wayside after Michael broke free, so Dean ends up granting his brother root access to his head in a fleabag motel.

Get on the bed, Sam orders. I want you lying down for this.

He pulls back the covers and Dean gets in. Sam, he says as his brother tucks him in. Wait, Sam.

Sam sits down at his bedside, oddly parental.

You ready?

As ready as I’m ever gonna be.

Sam _sinks_ into him.

He’s unobtrusive at first. The first memories are from their childhood, Sam centric, Dean thinks, and so he defers to Sam’s better judgment when his brother flips a few details.

What happens if _your_ memory is faulty, Dean asks as they fly through Sam’s preteen years. 

This is a valid concern. They told so many stories, both Dean and Dad, and Dean thinks that some of them have replaced history in his memory, and there’s definitely more than a fifty percent chance that the details he remembers don’t match up with the version he told Sam.

Sam goes silent.

Sam? Dean prods.

That week after you came back from Sonny’s, Sam says. The one we spent in Chinatown, where I ended up mutilating your back.

What about it?

How much do you remember?

Skip it.

Can’t.

And then Dean _sees_ Sam, not the floppy haired boy he was when Dean was finally released from exile, but the giant he grew up to be, horrifically incongruous against the backdrop of his youth.

Michael’s here, Sam says. I can’t let him get away.

Wait, Dean tries to say. Sam!

Sam pauses.

I can hold him, Dean thinks frantically. He doesn’t remember much from that week, his memories blurred by time and pain and blood and Michael, but it’s a distinct block of haziness. Dean can build a fortress around it.

That’s not how it works, Sam says urgently. He’s hiding in the bugs, Dean, and he’s going to kill you if I don’t dig him out.

What bugs, Dean demands. God, Sam, what are you talking about, what bugs?

The ones I dug out of your back, Sam snaps. He runs his hand through his hair, tightens it into a fist and brings it close to his mouth. God, Dean, I said I wouldn’t do this again, but there’s no other way. Just. Just close your eyes.

What are you talking about, Dean says, scrambling back.

Hush, Sam says, and he reaches out —

 

6.

— wake up, Dean, wake up!

Dean’s in his own private Mystery Spot.

Sam, he gasps, and his brother’s face swims into focus.

Thought I lost you, Sam babbles, tears and snot mixing like he’s five again. I fucked up, I fucked up, oh God I fucked up so bad.

I feel fine, Dean says immediately. Good as new.

That’s because you are, Sam says, and then he shudders under the weight of a horror Dean doesn’t remember. God, Dean, I had to remake you.

He’s meant to be discomfited, Dean thinks. Sam probably thinks he’s outraged because of autonomy and all of that.

You did a good job, Sammy, he says instead. I don’t feel any different.

He feels better, even. He doesn’t feel like the Dean of 2019 is feuding with the Dean of 1995.

I fucked up, Sam says again. There’s no way we can continue now. I’m the worst Arthur ever and I can’t verify for shit.

Dean reaches up. Wipes his brother’s face clean. Let’s go back to the bunker, he says.

Sam drags his sleeve across his eyes.

No.

 

 

7.

Sam’s careening down the 101.

Where are we going, Dean asks, again, and Sam grunts in that special non-communicative way he has.

They’re not going back to the bunker. The machine’s useless, Sam said, vicious and furious. All it’s gonna do is smear Michael all over your memories. Is that what you want?

So here they are, roaring down the empty highway at six in the morning, hoping to beat the LA rush hour.

My contact lives in Arcadia, Sam says.

Didn’t that chick live there, Dean says. The one who worshipped Lucifer. Or Vince Vincente.

Maybe, Sam says with a one-shouldered shrug. Does it matter? We’re not looking for her anyway.

They don’t beat the rush hour, but it doesn’t really matter, because Sam’s contact is happy to wait.

John Winchester’s boys, she says when she opens the door. I’ve been expecting you two for a very long time.

We need to know what happened that night, Sam says bluntly. His brother once believed in introductions and small talk and niceties, but that was a small eternity ago and now his brother is a kinder version of their father.

If she expected better, she makes no indication.  Come with me, she says, toeing on a pair of sneakers. This way, it’s in the garage.

There’s a tiny detached garage at the edge of her property, and a beat up Camry parked near it. She gets into it and fishes around in the compartment, and then the garage door slowly rises with a creaking moan.

What’s in there, Dean asks, mouth suddenly dry.

What we put into your back, she says.

What do you mean put, Sam says. Did you put the bugs in his back?

I did, she says placidly. At John’s request. Think of it as a vaccination.

Against what, Sam asks, and Dean catches just the slightest tremor in his brother’s voice before it rises in anger. You handed me that knife in the motel and told me to dig. What kind of vaccination demands field surgery?

She hums a little under her breath. A vaccination against Azazel, she says at length. A vaccination both against you and for you too, I suppose.

What do you mean, Sam says, and there’s an undercurrent of violence in his voice.

It was a long shot.

A long shot for what, Dean says hoarsely.

For keeping your brother human.

Sam flinches.

Liar, he says at last. No bugs could have gotten rid of the demon blood.

We weren’t trying to do that, she says gently. We thought about it, but you’re right – nothing on earth is toxic enough to combat that kind of blood. But these aren’t ordinary bugs either, you know. We call them _gu_.

It’s a name that Sam recognizes, Dean thinks. That much is clear from the way he blanches.

You used my brother as a host to birth your murderous bugs?

We used him to host the mother.

But why kill the bugs, Sam demands. Why go tearing through his back if the bugs are supposed to devour each other anyway?

She regards him with pity.

 _Gu_ , she says, isn’t a synonym for bugs.

I know, Sam says impatiently.

I don’t think so, she says. _Gu_ is a collection of poisonous creatures that devour one another until only one is left standing.

I know that, Sam snaps.

Creatures, she says coldly. You were the last one standing, Sam Winchester. You became _gu_ that night, as did your brother. I bound you two together, and that connection was the only thing that kept you _good_ during Azazel’s games.

Did you really think you were better than the rest?

Azazel couldn’t claim you as one of his because you already belonged to your brother.

And look at you now, she says in disgust. Your eyes are yellow.

 

8.

They leave her house at noon. Sam doesn’t stop at a diner or a fast food joint – he pulls into the local Plucky Pennywhistle’s and parks the car.

The hunt after Chinatown, Sam says apropos of nothing, as they sit marinating in the sweltering heat. Do you still remember it?

Dean mostly remember claws, the fetid stench of werewolf breath, the wetness, the drool, the blood. But that’s not what Sam’s talking about. Sam’s talking about that stretch of days he spent at Plucky Pennywhistle’s when Dean was holed up in the library researching.

I remember you were scared of clowns after that hunt, Dean says dutifully.

He bound me to you and then took you away, says Sam, and he looks at Dean with a wry smile. It took me a while to get used to it.

Dean thinks about Sam at twelve, the times he left Sam alone in a motel, the quiet worry that was always present at the back of his mind.

You never had a chance to live your own life, Sam says, eyes fixed on some distant point outside the car. Dad entangled us and you got the short end of the stick.

Don’t you think that, Dean says fiercely. If Dad had given me a choice, I’d have said yes in a heartbeat.

He means every word.

I’d have too, Sam says quietly. Maybe that’s why he didn’t even bother to ask us.

There’s no point to this conversation then, Dean tries to say, but his voice is gone.

Just. Just let me finish, okay, Sam says rapidly, like if he doesn’t get the words out now he’ll never be able to say them. Dean, I asked her if there was a way to sever the link, and she said that if I left the rest of Michael in you, the link would erode eventually.

So I’m asking you now: what do you want?

 

 

9.

Sam wants to talk about physics, about ground states, about how Dean’s life is a Hamiltonian and Dean still has no idea what his true self, free from Michael or Sam looks like. Sam wants to talk about free will.

Sam, Dean says patiently. I came back from Sonny’s for you, and that was before the deal with the bugs.

You don’t get how it works, Sam says insistently, and he’d be convincing if his voice didn’t crack halfway through. Dean, we’re _entangled_. You don’t get to make your own decisions. Hell, you don’t even know what decisions you want to make.

What goes unspoken is this: would you still have put yourself through forty years of hell underground and then another ten just for this?

Sam, Dean says again. Entanglement has nothing to do with free will.

What goes unspoken and is no less true is this: yes, always.

 

10.

You can’t leave Michael in me, Dean says point blank. You don’t get how entanglement works. You leave him in me long enough and I’m gonna be entangled with him instead of you.

That’s not how entanglement works, but there’s no point in arguing with Sam about his pseudo physics bullshit. Dean thinks about Michael inside the tiny bugs that burrowed under his skin so many years ago. He thinks of Sam, a blur inside his head, too amorphous to stop Michael as he escapes into other memories, and then there’s Michael peering into that awful night at Cold Oak, Michael looking at Lucifer wearing Sam and a white suit, Michael watching his brother fall into a pit, and he’s so nauseous that he wants to dig into his skin with a knife.

You gotta get him out, he says, and his voice sounds like it’s coming from another body. Sam get him out get him out get him —

Stop it, Sam says roughly, and Dean feels Sam shake him. Dean, you need to stop scratching.

Dean looks down.

There’s blood under his fingernails and marks on his arms.

 

11.

Distillation, Sam says at last. There are bags under his eyes and there’s a trickle of blood above his lips and it takes Dean a moment to realize that they’re no longer in the car.

Where are we, he asks, and Sam just looks even more upset.

In the same motel room we’ve been in for the last week, Dean.

We were at Plucky’s, Dean says, grasping for his memories.

And then you fainted and I had to get you to a bed as fast as I could.

Dean presses a hand to his head. He doesn’t feel faint, but he doesn’t feel much at all.

What’s going on, Sammy, he asks quietly.

Michael tried to kill you. Your body’s been falling apart for a while now.

So what’s keeping me alive then?                                                     

Sam scrubs his sleeve across his nose.

It comes away red.

Distillation, Sam says again. I’m gonna maximally entangle us to save you.

 

12.

Maximal entanglement, Sam reminds Dean, is not to be taken lightly.

What it means, he says, is that from now on, whatever happens to you, happens to me.

They’re already like that, Dean thinks. Sam dies and he sells his soul. He dies and Sam goes dark side. You touch Sam and you hurt Dean. You hurt Dean and you get Hurricane Sam.

There’s more, Sam says. Dean doesn’t need to speak now for Sam to figure out what he’s thinking. Telepathy’s one of the perks when you’re keeping your brother’s body running through sheer will power.

I’m the king of hell, Sam says. I’m gonna live forever, and by the time I’m done, you will too.

 

 

13.

Sam wants to go back to the bunker.

You said it was a tomb, Dean points out. What’s changed now?

We need to get Cas back into his own vessel, Sam says sharply. Cutting Michael loose isn’t going to be fun and I don’t want to hurt him.

Cas is back inside of my head?

He’s helping me keep you alive.

It’s not until Dean’s back inside the bunker, ensconced in his room and tucked into his bed that he realizes Sam brought him back into the bunker precisely because it is a tomb.

It’s a tomb for the Winchesters, dead or alive.

Wait, Dean says suddenly. What happens to you if Michael really leaves me blood and bone?

He has a vision of Sam chained to his brain dead brother for all eternity, and it chills him to his bones.

That’s not what I’m afraid of, Dean, Sam says. Michael’s already tried to do that, but you’re still here, aren’t you?

Then what are you afraid of?

Sam doesn’t reply. He keeps looking at Dean, eyes unbearably soft, and Dean reaches out from under the covers to take Sam’s hand.

I’m gonna do my best to fight, he promises. I’m not gonna leave you alone for the rest of eternity.

You might want to, in the end, Sam says seriously. I’m using my power freely now, and that’s not something I can stop. You might not like who I become.

You’re Sam, Dean says, and this time he means it with all his heart. He knows his brother, and he knows what his brother will be like in a hundred years, a thousand, an eternity.

You say that like it’s a good thing, Sam says, and he bows his head, a little bashful and a little self-conscious, like that boy Dean raised so many years ago.

Remember, we’re maximally entangled, Dean reminds Sam.

Maximal entanglement isn’t necessarily preserved under time evolution, Sam says, and Dean can see that that’s something that’s been weighing on his brother’s mind. It might not be forever, Dean, and even if it is, what if it goes sour?

Then we’ll deal with it, Dean says.

Okay, Sam says.

Just like that?

Yeah, Sam exhales shakily. Listen, Dean, I want you to know just exactly what I’m gonna do to force Michael out.

You’re gonna use that Metropolis thing again, aren’t you?

I fucked up the last time because I had no idea what really happened that night, and you _collapsed_ , Dean, I fucking unraveled you and had to remake you and it was the most awful thing I’ve done.

But you’re not gonna fuck up again, Dean says confidently.

Sam shakes his head.

I won’t, he vows, but that’s not why I need you to know what I can do. Dean, promise me. If I ever try to do this again to you. If I ever try to remake you after I get Michael out of you. You gotta stop me, Dean. Get into my head. It goes both ways. You gotta take the reins if I really go dark side.

What do you mean, Dean tries to say, but Sam has once again temporarily silenced his voice.

Don’t, Sam says. Put yourself first for once.

He holds Dean’s gaze until Dean looks away and nods.

Good, he says with satisfaction, and smiles for the first time in ages.

Dean stares, transfixed, and his brother lays his hand over Dean’s eyes.

Close your eyes, Dean.

 

14.

All that’s left to know is _Sam, Sam, Sam_.

**Author's Note:**

> 1) This is pseudoscience masquerading as hurt/comfort and I have no regrets.  
> 2) The quantum metropolis algorithm I have in mind can be found in a 2009 paper by Temme et al. Its arXiv reference number: arXiv:0911.3635 [quant-ph].  
> 3) Gu is a kind of magic found in Chinese folklore. It's usually cast using venomous creatures.  
> 4) The second half of the title comes from Lana del Rey's _Ride_.


End file.
